This is a check source board for use with Fluke 451P, Fluke 451B, and Ludlum 26-1/2/3.  The geometry of the board will ensure consistent placement of meters when operational checks before use.  We have these placed within calibration labs as well as anywhere these meters are stored. Each jig has a nominally identical Cs-137 check source to ensure the meter reading is a reliable indication of meter operation.  The 3 meter cutouts are not perfect, but good enough for this type of check.  

20250306 - V7 added with grove to fit larger alternate check source, and a v-slot to accommodate placement of a “hot dog” probed meter.